The present invention relates to patient support systems capable of performing Trendelenburg therapy and more particularly to an apparatus for performing Trendelenburg therapy in a patient support system which supports at least a portion of the patient's body in an air fluidized mass of material.
Trendelenburg therapy is applied to patients suffering from any of a number of conditions. Trendelenburg therapy involves the elevation of either the patient's head or feet by about 7.degree. from the horizontal. Elevation of the feet of a patient to a position about 7.degree. above the horizontal plane while simultaneously positioning the patient's head at about the same angle below the horizontal plane is known as head Trendelenburg therapy or as simply Trendelenburg therapy. Similarly, elevation of the patient's head to a position about 7.degree. above the horizontal plane while simultaneously positioning the patient's feet at about the same angle below the horizontal plane is known as foot Trendelenburg therapy or as Reverse Trendelenburg therapy.
Most conventional hospital beds provide apparatus for elevating the head and feet of a patient to perform head and foot Trendelenburg therapy. In some beds, this apparatus constitutes a hand manipulated crank or ratchet. In other beds it is a scissors jack arrangement, while in still others it resembles a screw jack arrangement. In yet other embodiments, the apparatus includes gas springs which are released manually to place the head or foot section of the bed into the 7.degree. uneven elevated position.
In an air fluidized patient support system such as disclosed in U.S. Pat. Nos. 3,428,973 to Hargest et al, 4,483,029 to Paul, 4,564,965 to Goodwin, 4,599,755 to Tominaga, and 4,637,083 to Goodwin, which are hereby incorporated herein by reference, the weight of the fluidizable mass of material renders uneven elevation of the head and foot of the bed impracticable, if not impossible.